Laminated Busbar: Core Connectors And Technical Analysis Of High-Power Systems

In the fields of new energy vehicles, industrial inverters, energy storage systems, etc., the efficiency and reliability of power transmission directly affect the performance of equipment. Laminated Busbar, as a multi-layer composite conductive component, has become a core connector for high-voltage and high-current scenarios with its characteristics of "low inductance, high integration, and easy heat dissipation". This article will start from technical parameters, structural design and application scenarios to reveal its professionalism and industry value.

 

 

 

 

1. Material and structure
Laminated Copper BusBar uses copper (mainly T2 copper) or aluminum as the conductive layer, the thickness of a single conductor is 1-3mm, and the conductive cross-sectional area is customized according to the current demand (typical value 50-500mm²). The insulation layer is made of PET, PI (polyimide) or Nomex, with a thickness of 0.1-0.5mm, a dielectric strength of 25-100kV/mm (such as PI material with a withstand voltage of more than 100kV/mm), and a flame retardant grade of UL 94 V-0, which meets the wide temperature range requirements of -40℃ to 120℃ (PI/Nomex can reach 220℃).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. Electrical performance
Low inductance: The electromagnetic fields between layers cancel each other out, and the stray inductance is as low as 10-50nH (the inductance of traditional wiring harnesses reaches μH level), which effectively suppresses the voltage spike during IGBT switching (reduced by 30%-50%) and extends the life of the device.
Low impedance: DC resistance ≤0.1mΩ (100mm copper busbar, 2mm thick), voltage drop <2% (500A working condition), and supports a high current density of 4-6A/mm².
Distributed capacitance: Through the optimization of the insulation layer thickness and dielectric constant (such as PET dielectric constant 3.8), the capacitance value can reach 10-100nF, compensating the high-frequency ripple of the system.

 

3. Thermal management parameters
The thermal conductivity of the copper-based busbar is 385W/(m·K), and that of the aluminum-based is 205W/(m·K). With the design of heat dissipation teeth or water cooling channels, the temperature rise is controlled at **≤30℃** (ambient temperature 40℃, 500A continuous current). The edge sealing process (epoxy resin spraying) avoids dust accumulation and improves heat dissipation consistency.

 

4. Mechanical and safety
Flatness ≤0.1mm (100mm length), meeting the requirements of precision installation; creepage distance ≥10mm (700V system), electrical clearance ≥10mm, passing the DC 3500V/60s withstand voltage test (leakage current <2mA). Surface treatment options include tin plating (above 5μm) and silver plating, and the salt spray test exceeds 500 hours.

 

 

1. Layered structure design
Adopt "conductive layer-insulating layer-conductive layer" sandwich structure, and achieve gapless bonding between layers through hot pressing process (150-200℃, 5-10MPa). For example, the Automotive BusBar of new energy vehicles is often designed with 3-5 layers, with positive and negative busbars stacked in a layered layout, and a capacitor layer embedded in the middle, to achieve low inductance and energy storage simultaneously.

 

2. Customized molding
Supports processes such as bending, convex hull, and riveted copper columns to adapt to complex spaces (such as motor controller U/V/W phase-differentiated busbars). A photovoltaic inverter busbar case shows that through L-shaped bending and bolt hole pre-positioning, the installation efficiency is increased by 70%, avoiding the risk of misconnection of traditional wiring harnesses.

 

3. Edge processing technology
Open edge (low cost), epoxy resin edge sealing (IP65 protection), and glue sealing (moisture-proof) are optional. The Copper Bus Bar for Alternative Energy of the mining inverter adopts a full glue filling process, which is resistant to vibration (5-500Hz, 20g) and dust environment, and the MTBF (mean time between failures) exceeds 50,000 hours.

 

 

1. New energy vehicles
In the 800V high-voltage platform, the laminated busbar connects the battery pack and the motor controller, carrying a peak current of 1500A (such as the PDU busbar of a certain model). The actual measured data of a certain enterprise shows that the use of copper-based laminated busbars (thickness 2mm, cross-sectional area 200mm²) reduces the system inductance from 800nH of the wiring harness to 35nH, and the motor torque response speed is increased by 15%.

 

2. Industrial inverter
The Laminated Bus Bar for High Frequency Inverter of the medium-voltage inverter (3.3kV) needs to meet the creepage distance of 40mm. Through the Nomex insulation layer (0.3mm) and nickel-plated surface treatment, it can operate stably in the humid environment of the coal mine, and the temperature rise is 12℃ lower than that of the traditional copper busbar.

 

3. Energy storage and photovoltaic
In large energy storage containers, the laminated busbar is connected in series with 200Ah cells, supports 2C charging and discharging (400A), and with the water cooling plate design, the temperature difference of the whole cabinet is less than 5℃, extending the battery cycle life to more than 6000 times.

 

 

 

With the popularization of silicon carbide (SiC) devices, laminated busbars are developing towards "high frequency and ultra-thinness". For example, a 0.8mm ultra-thin copper busbar developed by a certain company, with 20μm PI insulation, has an inductance as low as 8nH and is suitable for 200kHz switching frequency. At the same time, the penetration rate of aluminum-based busbars (40% lower cost than copper) in photovoltaic inverters has increased, and through surface anti-oxidation treatment, the weather resistance is more than 25 years.

 

The technical value of Laminated Bus Bar for Electric Vehicle Power Electronics lies not only in parameter indicators, but also in its overall optimization of system energy efficiency. From material selection to process control, from electrical performance to thermal management, each parameter is based on the ultimate pursuit of reliability and efficiency. In the wave of new energy and industrial automation, laminated busbars are playing the role of "power highways" to support the safety and innovation of high-power systems.